Bleached condensation product of carbohydrates and crude hydrocarbons



aldehydes,"orboth.

In-co=pending applications of Jaeger, 'SerlaLNo. 512,500- filed January '30} 1931, Serial 'No. 512,752

Patented Jan. 2, 1934 lam-scum; CONBENSATIONWPRODUCT 0F omnenmnamsmnn @onomr omens Alphonso; ulian-Mount Lebanon, and-Heinrich I wzivnmmnaramma, assignorsto'lheselden. ('Jompany, Pittsburgh, Pa, a corporation 0t) l st m-m, ion February 19:11:

swarm. 518,291 I 4 (01., 260-2) Thi invention-relates to:condensation -prodnets of carbohydrates aromatic hydrocarbons and sulfuric acid which {may or may--not'- also such as phthalio'anhydride; I

. i amount of: oxidizingagent willnaturally varyito some-extent with the nature of the-condensation product-and its impuritles we "have found that in generalwi'th" condensation products contain-* January 31, 1931,condensation products ofcrude ing cellulose and residues'from tliepurific'ation m aromatic hydrocarbons or residues from the puricontain organic acids filed. January 31, 1931 andScrial- Noi 51 2,753-filed fication of aromatic hydrocarbons are condensed with carbohydrates'an'dsulfuric-acid or withcanbohydrates treated-with phthali'c' anhydrideand sulfuric acid, the products being tanningagents.

15 "While the tanning power of the products is excellent and-the raw-material lsf-very cheap, many of the products are open to the-objection that they are highly colored, this being particularly true of the products obtained from crude residues from the purification of aromatic hydrocarbons,

some of which are black orvery dark brown and are, therefore, objectionable when used with light colored leathers.

Similarly, tanning agents obtained by the sulfonation of crude aromatic hydrocarbons or other residues which are described in the co-pending application of J aeger and Witzel, Serial No. 518,- 292 filed February 25, 1931 are likewise very dark in color. The condensation products of cellulose, crude aromatic hydrocarbons and sulfuric acid when reacted with aldehydes as described and claimed in the application of Jaeger and Witzel,

' Serial No. 520,456 filed March 5, 1931 likewise present problems in tanning due to their high color.

Tanning agents obtained by the sulfonation of crude coal tar fractions such as anthracene oil, etc. may likewise be bleached by the process of the present invention. These tanning agents obtained by sulfonating crude coal tar fractions are described in the co-pending application of A. O. Jaeger, Serial No. 519,267 filed February 28,

, According to the present invention, we have found that, surprising as it may seem, the condensation productsmay be bleached with oxidizing agents, for example hypochlorites, either in the preformed state or formed in situ by the use of chlorine, which decolorize the highly colored products, transforming them into relatively light colcred material, varying from a yellow to a light brown, which can be used even in the tanning of light coloredleathers and which show no no-.

great excess oi oxidizing agent/"is used? If too- .large-an-excess of oxidizing agentis-used' the an 'ning power is lessened, and 'if' a sufilc'ient excess is used it may be-entirely destroyed; While the of aromatic hydrocarbonssuch as crude anthracene should not be treated with more than 50% of their weight of thefoxidizing agent'andusually 10% ives better results-1 I-naddition to the-hypohalites, other-oxidizing agents maybe'u'sed suchas chlorine in acid ;solution, chromic acidgpotassium pennanganateyetc and; ifdsiredymixturesmaybe used: Irr'case' of chromic acid, the reduction product is itself a tanning material.

The constitution of the condensation products involved in the present invention is not definitely known and the action of the oxidizing agent is likewise not definitely proven. Nevertheless, we

Example 1 I 50 parts of the black granularmass obtained according to Example 1 of the Jaeger application Serial No. 512,500 filed January 30,1931 and which is the condensation product of the residue from the purification of crude anthracene by means of furfural, cellulose and sulfuric acid are mixed with 500 parts by weight of water and vigorously stirred for one hour. 400 parts of a water solution containing 10.84 parts of NaOCl is. vigorously stirred in. The stirring is continued for about two hours, the color of the liquor changing from dark brown or black to dark yellow or very light brown. On evaporation, a solid is obtained which is readily soluble in water. and shows good tanning powers Instead of using sodium hypochlorite, chlorine maybe passed in, the solution being kept sufficiently alkaline to assure good absorption of the chlorine. The amount of chlorine passed in man January 31, 1931, in the formof its sodium salt should, of course, correspond to about sodium hypochlorite.

Instead of using hypohalites, potassium permanganate or chromic acid may be used.

Example 2 Example 3 A condensation product of cellulose treated with phthalic anhydride, the residue from the solvent purification of anthracene and sulfuric acid, prepared as described in Example 1 of the application of A. O. J aeger, Serial No. 512,753 filed is treated with a hypochlorite as described in Example 1. A very marked lightening in color is obtained without substantially affecting the tanning power of the material.

Example 4 The condensation product of cellulose, the residue from the solvent purification of crude anthracene, sulfuric acid and formaldehyde,as

adescribed in Example 1 of theJaeger and Wit zel application Serial No. 518,292 filed February 25, 1931, above referred to, in the form or its sodium or calcium salt is treated with a hypochlorite as described in Example 1. The brownish black liquor is transformed into a light brown or brownish yellow, and retains its tanning powers.

What is claimed as new is: 1. A process of producing light colored tanning agents, which comprises condensing at least one carbohydrate, phthalic anhydride and at least one impure aromatic hydrocarbon with sulfuric acid and'subjecting ,a dispersion of the soluble condensation product obtained to the action oi a bleaching agent in amounts suflicient to substantially lighten the color, but insufficient to destroy the tanning properties thereof.

2. A process of producing light colored tanning agents, which comprises condensing at least one carbohydratawphthalic anhydride and at least one substance belonging to the group consisting of residues from solvent purification of crude anthracene with phenanthrene and carbazole solvents, residues from solvent purification of crude anthracene with phenanthrene solvents, residues from the vaporization of impure anthracene, residues from the vaporization of crude naphthalene, with sulfuric acid and subjecting a dispersion of the condensation product obtained to the action of a bleaching agent in amounts suiiicient to substantially lighten the color, but insuflicient to destroy the tanning properties thereof. a" V l 3. A process according to claim 1, in which the bleaching agent is a hypohalite.

;4. A process according to claim 2, in which the bleaching agent is a hypohalite. 

